Sleep trackers may mislead users about sleep quality, study finds

A recent review finds wrist-worn sleep trackers like Fitbit and Apple Watch may not accurately reflect how well users actually slept, particularly for those with insomnia, potentially delaying proper clinical care. Published in Sleep Medicine by Duke and Mayo Clinic researchers, the analysis of five studies with about 2,000 participants showed devices explained only 2.5 to 16.2 percent of subjective sleep quality differences. Trackers often failed to detect nighttime awakenings, overestimating sleep time by roughly half an hour in insomnia patients. The review advises that device data shouldn't replace validated subjective assessments like sleep diaries, especially for older adults or those with depression. While useful for tracking duration patterns, experts caution users not to stress over readings, as poor agreement suggests potential misleading information.